Given data:
The given point at which Desiree's house located is (-8,6).
The equatiion of the line is y=15x+6.
The standard expression for the equation of the line is,
y=mx+6.
Compare the given equation with the standard equation of the line.
m=15.
The expression for the slope of the linne which is perpendicular to the given line is,
15(m')=-1
m'=-1/15.
The expression for the equation of line of the Desiree's driveway is,
y-6=(-1/15)(x-(-8))
15(y-6)=-x-8
15y-90=-x-8
15y+x-82=0
Thus, the equation of line of the Desiree's driveway is 15y+x-82.